Electricity calculator
Appliance Wattage Cost Calculator
Calculate running cost for one or more appliances from wattage, quantity, daily hours, monthly days, and kWh rate.
When to use this calculator
Use this calculator for groups of similar devices: multiple fans, several lights, heaters in different rooms, chargers, pumps, TVs, computers, or kitchen appliances. Quantity matters when small loads are repeated.
It is useful for finding hidden cost drivers. A single small device may not matter, but ten devices running for long hours can become noticeable.
Formula used
Cost = watts ÷ 1,000 × quantity × hours per day × days × electricity rate.
The formula is intentionally simple so it can be used for quick planning. Real bills, quotes, and installation costs can include fixed fees, taxes, tiers, labor, product limits, and site-specific conditions that a calculator cannot see.
Input guide
| Input | How to use it |
|---|---|
| Watts | Power draw for one unit. |
| Quantity | Number of identical or similar units. |
| Hours and days | Average running schedule. |
| Rate | Local electricity cost per kWh. |
Examples
Multiple fans
Five 70 W fans running 8 hours daily use 84 kWh per month.
Always-on devices
Low wattage becomes important when a device runs 24 hours a day.
How to get a more accurate result
- Group similar devices rather than mixing very different wattages.
- Use measured watts for electronics with sleep modes.
- Check whether devices are truly on or only plugged in.
Common mistakes to avoid
- Ignoring quantity.
- Counting standby as full operation.
- Using one appliance's wattage for a different model.
Quick checklist before relying on the result
- List devices.
- Group by wattage.
- Estimate hours.
- Calculate monthly and yearly cost.
FAQ
Can I calculate a whole room?
Yes, if you group devices carefully or run separate estimates and add them.
What about standby power?
Use a plug meter for standby if it matters.
Why include quantity?
Many small devices can equal one larger load when they run together.